It’s taken the musical “Cats” nearly 40 years to make its way from the stage to the big screen. Now we know why.

Just as there are some novels that defy dramatization, so there are stage productions that derive their power from the interaction of audience and performer, that work precisely because the viewer realizes that all the magic unfolding in front of him/her is being created by real people in real time.

Tom Hooper’s movie version, on the other hand, has been so digitally diddled with that we can’t be sure that anything we’re seeing — from the settings to the performers’ faces — is even remotely real. Characters do impossible flips in the air, cockroaches march in formation…it’s all so artificial that the film might as well have been done as pure animation (actually that was the plan, back in the ’90s).

That said, the movie “Cats” isn’t a total wipeout. The score (the tunes are by Andrew Lloyd Webber, the lyrics derived from T.S. Eliot’s book of poems Old Possum’s Book of Practical Cats) remains humworthy and at least a couple of the performers manage to transcend their hairy makeup (all too often they look like werewolves from a ’60s Hammer film) and establish an emotional connection with the audience.

A big problem is that “Cats” lacks a real story. On stage this wasn’t a deal breaker…the show was a musical revue with different “cats” taking center stage to sing and dance their signature numbers. What plot there was dealt with the approaching Jellicle Ball where one lucky feline will be chosen by the ancient Deuteronomy to be reincarnated into a new life (cats get nine of them, after all).

The screenplay by Lee Hall and Hooper centers on Victoria (ballerina Francesca Hayward, who seems capable of expressing only a quizzical attitude), abandoned by her owner in a dirty alley and adopted into the Jellicle tribe. Her guide and guardian is Munkstrap (Robbie Fairchild), who introduces her to various other characters and the rundown corner of London they call home.

That comment from a resident of Istanbul, Turkey, pretty much sums up the ethos of “Kedi (Cat),” a nonlinear documentary about that city’s vast population of semi-feral street felines.

Director Ceyda Torun’s film offers no scrolls of relevant statistics; no testimony by animal control officers, city fathers or health specialists; no fact-dispensing narration.

Instead we listen to everyday Istanbul residents talk about their relationships with the felines who share their lives. We marvel at some of the most amazing cat footage ever.

The tens of thousands of cats who live on Istanbul’s streets aren’t wild, exactly. They may not have owners as such, but most have struck up lasting relationships with one or more humans.

The cats receive food, grooming and occasional medical care; the humans report a significant improvement in their lives. (One fellow claims his cat buddies cured him of mental illness; now he devotes big part of every day and a substantial chunk of his income to feeding them.)

These aren’t your stereotypical cat ladies. They’re shop owners, cooks, fish mongers, pensioners, students and others who simply love living in a city where almost everywhere you look there’s a cat running, climbing, sleeping.

But the human/animal connections run deep. Says one young woman of her very first cat: “Let’s just say that if there’s an afterlife, I want to meet her again. Not my grandmother.”